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    Schinderhannes Bartelsi - The Origin Of Claws In A 390-Million-Year-Old Fossil
    By News Staff | February 5th 2009 12:00 AM | 4 comments | Print | E-mail | Track Comments
    A missing link in the evolution of the front claw of living scorpions and horseshoe crabs was identified with the discovery of a 390 million-year-old fossil by researchers at Yale and the University of Bonn, Germany.

    The specimen, named Schinderhannes bartelsi, was found fossilized in slate from a quarry near Bundenbach in Germany, a site that yields spectacularly durable pyrite-preserved fossils — findings collectively known as the Hunsrück Slate. The Hunsrück Slate has previously produced some of the most valuable clues to understanding the evolution of arthropods – including early shrimp-like forms, a scorpion and sea spiders as well as the ancient arthropods trilobites.

    Schinderhannes bartelsi
    Schinderhannes bartelsi.  Credit: Steinmann Institute/University of Bonn

    "With a head like the giant Cambrian aquatic predator Anomalocaris and a body like a modern arthropod, the specimen is the only known example of this unusual creature," said Derek Briggs, director of Yale's Peabody Museum of Natural History and an author of the paper appearing in the journal Science. 

    Scientists have puzzled over the origins of the paired grasping appendages found on the heads of scorpions and horseshoe crabs. The researchers suggest that Schinderhannes gives a hint. Their appendages may be an equivalent to those found in the ancient predatory ancestor, Anomalocaris — even though creatures with those head structures were thought to have become extinct by the middle of the Cambrian Period, 100 million years before Schinderhannes lived.

    The fossil's head section has large bulbous eyes, a circular mouth opening and a pair of segmented, opposable appendages with spines projecting inward along their length. The trunk section is made up of 12 segments, each with small appendages, and a long tail spine. Between the head and trunk, there is a pair of large triangular wing-like limbs — that likely propelled the creature like a swimming penguin, according to Briggs. Unlike its ancestors from the Cambrian period, which reached three feet in length, Schinderhannes is only about 4 inches long.
       
    Schinderhannes bartelsi
    A reconstruction of Schinderhannes bartelsi.  Credit: Elke Groening

    This finding caps almost 20 years of study by Briggs on the Hunsrück Slate. "Sadly, the quarry from which this fabulous material comes has closed for economic reasons, so the only additional specimens that are going to appear now are items that are already in collectors' hands and that may not have been fully prepared or realized for what they are," said Briggs. 

    Other authors of the paper are Gabriele Kühl and Jes Rust at the University of Bonn, Germany. Funding for the research was from the German Science Foundation and the Humboldt Foundation.

    Derek Briggs http://www.peabody.yale.edu/contact/index.html 
    Peabody Museum of Natural History http://www.peabody.yale.edu/ 
    background information on Anomalocaris http://paleobiology.si.edu/burgess/anomalocaris.html 
    Hunsrück Slate http://palaeo.gly.bris.ac.uk/Palaeofiles/Lagerstatten/Hunsruck/index.html

    Article: Science (February 6, 2009)

    Comments

    This article makes no sense. Schinderhannes is a dinocarid. Euripterids, spiders, and scorpions are chelicerates. They are not closely related. The earliest chelicerate is Sanctacaris, which lived the same time as Anomolocaris. Chelicerates, including scorpions, were already well diversified in the Ordovician period.

    rholley
    This also had me a bit confused.  Having been chasing through (mainly) Wikipedia for a good part of an hour, I find that the Anomalocaridids to which this creature belongs are a family within the Dinocarida which are a class within the phylum Lobopodia.  To get a handle on these, the ideal book is The Crucible of Creation: The Burgess Shale and the Rise of Animals by Simon Conway Morris (ISBN-10: 0192862022).

    The Lobopodia are, however, considered to be a stem group from which the Arthropoda are likely to have arisen.

    So where do Horseshoe Crabs come into it?  Their so-called "trilobite larvae" are cute (video), but closer examination shows that they are significantly different from trilobites.

    Interestingly, the generic name Schinderhannes comes from a German outlaw of the same name.

    If I can stop my head spinning from abstract algebra, though, I might get around to looking at what the paper in Science actually says.  Note to News Staff: references would be helpful.
    Robert H. Olley / Quondam Physics Department / University of Reading / England
    Hank
    Sometimes these are written before it has a citation (in this case, 1 day before) but because it's a Science mag study we still want to give them credit so we still use the publication date.   If we're reminded we can go back and edit it later.   In this case:

    Science 6 February 2009:Vol. 323. no. 5915, pp. 771 - 773 DOI: 10.1126/science.1166586

    Whenever we have funding and citation, we list them.
    rholley
    I've now read the paper, much of it during the breaks in American Idol, and your News Staff are exonerated.  It may be that the authors have a very wide definition of what constitutes an arthropod.

    Schinderhannes, although found in the Devonian,
    shows a previously unseen combination of the characters that occur in Cambrian anomalocaridids and euarthropods.
    So while Anomalocaris had disappeared, and things more like the creepy-crawlies we know and love had appeared, these beasties had, in perhaps more senses than one, remained "stuck in the mud".
    Robert H. Olley / Quondam Physics Department / University of Reading / England